This invention relates generally to wind turbines, and more particularly to methods of fabricating wind turbine rotor blades.
Recently, wind turbines have received increased attention as an environmentally safe and relatively inexpensive alternative energy source. With this growing interest, considerable efforts have been made to develop wind turbines that are reliable and efficient.
Generally, a wind turbine includes a rotor having multiple blades. The rotor is mounted on a housing or nacelle, which is positioned on top of a truss or tubular tower. Utility grade wind turbines (i.e., wind turbines designed to provide electrical power to a utility grid) can have large rotors (e.g., 30 or more meters in diameter). Blades on these rotors transform wind energy into a rotational torque or force that drives one or more generators, rotationally coupled to the rotor through a gearbox or directly coupled to the rotor. The gearbox, when present, steps up the inherently low rotational speed of the turbine rotor for the generator to efficiently convert mechanical energy to electrical energy, which is fed into a utility grid.
Known wind turbine blades are fabricated by infusing a resin into a fiber wrapped core. However, because the root section of the blade is thicker to accommodate high loads, known methods of infusing resins into thick parts do not always produce a defect free part within a cycle time that is no longer than the pot life of the infusion resin. One problem that can occur is the formation of dry spots where the infused resin has not reached. Some known solutions to these problems are to use added pre and/or post processes to infuse resin into dry spots. These solutions typically result in increased direct labor costs, increased part cycle time, and increased facilitation by machines or equipment for the additional processing.